Storage bags are commonly used for a variety of purposes such as storing food items. Such storage bags are typically made from a flexible, thermoplastic web material that is configured to provide an interior volume into which food items can be inserted. To preserve the inserted food, the storage bag may also include a closing mechanism, such as interlocking fastening strips, for sealing closed an opening through which the interior volume is accessible.
One problem that occurs with the aforementioned storage bags is that latent air may remain trapped within the interior volume after sealing closed the opening. The trapped air may cause spoiling or dehydration of the food items. To remove the trapped air, a one-way valve element may communicate with the interior volume. The one-way valve element allows for the evacuation of trapped air while preventing the ingress of air from the surrounding atmosphere into the interior volume. Methods of conveying the entrapped air through the one-way valve element include squeezing the flexible sidewalls to force air through the valve element or utilizing a mechanical evacuation device that can interface with the one-way valve element.
Where an evacuation device is used, the evacuation device typically operates by creating a pressure differential across the one-way valve element causing the valve element to open. Entrapped air can then be drawn from the interior volume through the one-way valve element by the evacuation device and exhausted to the surrounding atmosphere. Once the evacuation device is removed, the pressure differential between the surrounding atmosphere, typically at 14.7 pounds per square inch (PSI), and the interior volume closes the valve element. One problem is that the pressure differential used to open and draw air through the valve element may damage the storage bag. Another problem is that evacuating air from the interior volume may cause the flexible sidewalls to collapse in a manner that can damage the stored items.